Cylinder head with exhaust valve shield



H. F. STEVENS 2,691,969

CYLINDER HEAD WITH EXHAUST VALVE SHIELD Oct. 19, 1954 Filed Dec. 17, 1951 Fig.1 \\\\\\\\\\\I Harm 1-. Stevens mmvrox.

you q f Patented Oct. 19, 1954 UNITED CYLINDER HEAD WITH EXHAUST VALVE SHIELD Harm F. Stevens, Muizenberg, Cape of Good Hope, Union of South Africa Application December 17, 1951, Serial No. 261,944

1 Claim. 1

This invention relates to improved ways and means for protecting and prolonging the life and expected efficiency of exhaust valves in internal combustion engines and has to do, broadly construed, with a novelly cast cylinder head, one which though only slightly altered, is destined, it is believed, to increase the over-all performance and efficiency of an internal combustion engine using carburetted air.

It is a matter of common knowledge that exhaust valves are subject to overheating with the result that their efiiciency is diminished to an undesirable degree. The areal extent of the region in which the head of the valve works is also proportionately restricted and so the usual damaging blast of hot gas results in excessive heating of the exhaust valve, especially the valve-head. Then, too, these gases not only attack the vulnerable valve surfaces, they accumulate between the valve-head and overlying wall or partition of the cylinder head. Further, since the compression ratio is limited because of the detonation tendencies of the kind of fuel which is used (the exhaust valve being the unduly heated member) a lower temperature in the cylinder head may make it possible to proportionately increase the compression ratio without noticeably altering the standard mode of cylinder head casting, provided, of course, that the excessive overheating of the exhaust valves may be coped with.

A survey of the prior art has revealed that many and varied attempts have been initiated to solve the abnormal temperature problem in relation to exhaust valves. For example, watercooled valves have been oifered. Shields of one type or another have been put forth for use, apparently with little success. Evidently, what is holding up widespread adoption and use of these is the constant tendency of manufacturers to avoid undue intricate structural modifications effecting stock methods of manufacture and costs. Therefore, the object of the present endeavor is to structurally, functionally and otherwise improve on known prior art constructions and, in so doing, to provide a feasible adaptation in which manufacturers, retailers and users will find their manufacturing requirements and general needs fully met.

Accordingly, the instant invention is of the utmost in simplicity and economy and involves no alterations or changes in the cylinder block or usual poppet-type valves. Only the bottom wall construction of the water jacketed cylinder head is modified. That is to say, the partition above the intake and exhaust valves is partly altered, this directly over the exhaust valve by way of an annexed annular rib or ring for purposes of providing valve-head pocketing and shielding means, simple but highly effective as will be later seen.

Briefly summarized, the subject matter of the invention is characterized by an engine block embodying a cylinder head, a water jacket, the latter having a partition, a poppet-type exhaust valve operably reciprooable in said block with its head opening toward said partition, and a circular shallow pocket integral with the underside of said partition, the diameterof said pocket being slightly greater than the outer diameter of said head and the latter being adapted to recede into said pocket when opening, whereby to thus ward off the usual direct attack of damaging hot exhaust gases in the manner described and keeping its temperature down.

Other object and advantages will become more readily apparent from the following description and the accompanying sheet of illustrative drawmgs.

In the accompanying sheet of drawin s wherein like numerals are employed to designate like parts throughout the views:

Figure 1 is a fragmentary view showing the engine block, water-jacketed cylinder head with the improvements embodied therein and intake and exhaust valves, the exhaust valve being shown in its open protected position; and,

Figure 2 is a fragmentary bottom plan view of the cylinder head further emphasizing the nature of the improvements.

Referring now to the drawings by way of reference numerals and accompanying lead lines, the engine block is denoted by the numeral 4 and is shown provided with conventional poppettype valves. The intake valve is denoted by the numeral 6 and the exhaust valve 8. Neither the block nor the valves are in any manner altered and they may therefore be said to be conventional. The head of the exhaust valve, which is under consideration, is denoted by the numeral I0 and the conical or beveled underside is denoted at l2. The jacket-equipped cylinder head is denoted by the numeral l4 and this is a single casting, as is usual. It comprises top and bottom walls l6 and I8 and surrounding marginal walls 20 and 22 defining the usual water containing and circulating space 24. The elevated portion of the bottom wall, for convenience, is defined as a. partition and this is denoted at 26. The portion thereof 28 directly above the intake valve is in no manner altered. On the other hand, the portion directly above the exhaust valve is modified and this constitutes the improvement, in conjunction with the exhaust valve and other features. That is to say, this portion is formed with a depression 30 of circular form providing a correspondingly circular diaphragm 35. De-

pending .from the diaphragm and circumscribing the same is an endless rib or ring 34. The parts 32 and 34 define the protective pocket 36 for the valve head and it will be noticed that the corners 38 are slightly rounded and that thecrownof the rib is convexly rounded at 40.

It will be seen from the foregoing that all of I the parts illustrated are common or conventional features serve to ward off the usual direct attack 1 of damaging blast of hot disabling exhaust gases,

thus momentarily shrouding and shielding the .valve head against undesirable overheating. The

construction minimizes the likelihood of said gases, which are under pressure, from accumulating between the overlying partition, or rather the diaphragm 32, and valve head. The valve head in open position is secluded and finds refuge in the pocket 36. It is therefore partly protected. In addition, the rib 34 in conjunction with the underside [2 of the valve head provides collective gas deflecting and shunting surfaces with the result that the otherwise vulnerable surfaces of the valve head are isolated and thus protected. Not only this, scavenging of the combustion chamber is appreciably enhanced. This arrangement is calculated to reduce temperatures, allowing a higher comp-ression ratio and resulting in more economic and fast operating engine, especially for use in automobiles.

The distance between the lower edge of the ring or annulus and block is dependent on the required valve lift or stroke of the exhaust valve. The depth of the pocket may be made shallower or deeper to accommodate the required clearance and lift movement of the valve.

In operation it is understood that the exhaust valve functions as usual except that it is rendered more efficient in operation by the presence of the shroud or pocket means 36.

Minor changes in shape, size, materials and rearrangement of parts may be resorted to in actual practice provided no departure is made irom'the invention as claimed.

Having described the invention, what is claimed as new is:

In an internal combustion engine, an engine block embodying a cylinder head including a Water jacket, the latter having a partition, a poppet-type exhaust valve operably recip-rocable in said block "with its head opening toward said partition, and an endless rib cast integral with the underside .ofsaid partition, said rib extending below the plane of said underside and cooperating with the latter in providing a shield and defining a circular shallow pocket into which the valve-head may take momentary refuge when open, said pocket being .of a. diameter slightly greater than the-outside diameter of the valve-head, said rib completely encircling the periphery of the valve-head and the outer peripheral surface of said rib cooperating with the beveled underside of the valve-head and the exposed surfaces of the rib and valve-head and serving conjointly to deflect and shunt the hot gases away-from the vulnerable top surface-of the valve-head, whereby to better scavenge the gases and to, at the same time, completely shroud and protect said vulnerablesurfaces, the area ofsaid partition which is directly above said pocket being formed with a circular depression, said depression forming a short path for .radiating and carrying off the heat collected in the rib and pocket.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,074,859 Rich Mar. 23, 1937 2,076,590 Pope Apr. 13, 1937 

